•Rare case of PSTT limited to the vagina presenting eight years after last pregnancy and four years after hysterectomy•Differential diagnosis with other vaginal tumors can be challenging but it is critical because behavior and management are different.•Stage-adapted management is proposed and surgery is the mainstay treatment for localized disease.
Endometrial carcinoma (EC) is the most common cancer of the female genital tract in developed countries. Microsatellite instability (MSI), that represents 30% of EC, is an important prognostic and predictive biomarker. This status is assessed by detection of loss of MMR genes' proteins by immunohistochemistry (IHC) or by molecular biology. We aimed to compare the agreement between MSI status in IHC and molecular biology.
Methodology
Between January 2019 and December 2021, we conducted a monocentric retrospective study of 166 patients treated for EC (all stages) at the CHU of Liège. Sixty-seven patients were excluded. The remaining 99 patients had a complete IHC and molecular analysis for MSI. McNemar's test and a Kappa of Cohen coefficient were used to evaluate the agreement between the 2 methods.
Results
The McNemar's test demonstrated 41.4% and 39.4% of MSI in IHC and molecular biology, respectively (p=0.81). There were ten tumors with false-positive staining in IHC and MSS in molecular biology (specificity of 75.6%). Moreover, there were eight tumors with false-negative IHC but MSI-H in molecular analysis (sensitivity of 85.2%). The agreement between MSI in IHC and molecular analysis was 81/99 (81.8%) patients. The Kappa of Cohen coefficient was 0.62 (IC95%: 0.47–0.78), confirming the agreement between both techniques.
Conclusion
The methods of testing MSI by IHC and molecular biology are clearly concordant. Presence of MSI in IHC can be considered as a reliable surrogate test for MSI molecular status. Moreover, IHC testing is quicker, easier to perform and less expensive. Nevertheless, based on a 25% and 15% rate of false positivity and negativity respectively, consideration should be given to confirm MSI IHC status for all patients by molecular analyses.
Abstract Lymphangiogenesis, the formation of new lymphatic vessels, occurs in primary tumors and in draining lymph nodes leading to pre-metastatic niche formation. Reliable in vivo models are becoming instrumental for investigating alterations occurring in lymph nodes before tumor cell arrival. In this study, we demonstrate that B16F10 melanoma cell encapsulation in a biomaterial, and implantation in the mouse ear, prevents their rapid lymphatic spread observed when cells are directly injected in the ear. Vascular remodeling in lymph nodes was detected two weeks after sponge implantation, while their colonization by tumor cells occurred two weeks later. In this model, a huge lymphangiogenic response was induced in primary tumors and in pre-metastatic and metastatic lymph nodes. In control lymph nodes, lymphatic vessels were confined to the cortex. In contrast, an enlargement and expansion of lymphatic vessels towards paracortical and medullar areas occurred in pre-metastatic lymph nodes. We designed an original computerized-assisted quantification method to examine the lymphatic vessel structure and the spatial distribution. This new reliable and accurate model is suitable for in vivo studies of lymphangiogenesis, holds promise for unraveling the mechanisms underlying lymphatic metastases and pre-metastatic niche formation in lymph nodes, and will provide new tools for drug testing.
